The present invention relates generally to an improved reciprocating punching mechanism, and more particularly to a high speed heavy duty reciprocating punch device especially adapted for use in connection with thin flexible film materials. The punching mechanism is adapted to handle multi-ply films wherein the cumulative thickness becomes substantial. The punch apparatus includes relatively movable punch and die assemblies, the punch assembly having a cutter adapted to pass through the surface of the film at the point of the die so as to form openings, holes or slots within the film material passing through the working zone between the punch and die. Clamping shoe means are provided for retaining the flexible film material in taut disposition during punching, and in addition, means are provided for ejecting or removing the slug of film material which is obtained or formed upon a punching operation or event. Improved drive and control means are provided which utilize a double acting cylinder for extending and retracting the punch, and, in addition, a separate valve and control means is provided for delivering compressed air to the slug ejecting apparatus.
In the forming of holes or slotted openings in thin film materials, it is extremely important that the location of the holes be accurately positioned. Furthermore, products frequently demand the formation of clean, non-scalloped openings or bores in the film, and ragged or scalloped surfaces are accordingly undesirable and may contribute to the generation of scrap. Furthermore, film materials may be abrasive and cause considerable wear on punching equipment, and the extent of wear or lack of sharpness of the cutting tool becomes a less critical factor when the clamping apparatus of the present invention is being employed on the film. The improved drive and control means of the present invention provides for reliable operation of the punching apparatus, with the drive function and the ejection function being rendered independent, one of the other.